| 摘要 |
PROBLEM TO BE SOLVED: To provide an environmental consistency type precoated steel plate containing no chromium in its film or coating film and excellent in coating film peel resistance and corrosion resistance in its slide part. SOLUTION: In the precoated steel plate wherein a surface conditioning treatment layer comprising a metal such as Ni, Co or the like or a metal oxide or the like thereof is formed on the surface of a galvanized sheet and if necessary, a chemical forming treatment film is formed on the surface conditioning treatment layer, and an undercoating film and a topcoating film are further formed, a resin contained in the undercoating film is a resin mainly comprising a modified polyester resin, which is obtained by reacting a polyester resin with a number average molecular weight of 12,000-26,000 and a glass transition temperature of 0-30°C and an epoxy resin in a predetermined molar ratio, and a curing agent. The undercoating film contains a calcium ion-exchanged silica rustproof additive, a phosphate rustproof additive and/or a phosphite rustproof additive in a specific ratio. The chemical forming treatment film, the undercoating film and the topcoating film contain no chromium compound. COPYRIGHT: (C)2004,JPO&NCIPI |
